Pro-European party D66 made the strongest gains in Thursday’s European elections in the Netherlands, according to an Nos television exit poll.

The preliminary Ipsos poll put the Christian Democrats on 15.4% and D66 on 15.3%, ahead of Geert Wilders’ anti-Islam PVV, which went down from 17% to 12.7%.

Brussels has stopped the Netherlands publishing the official results ahead of Sunday’s vote in most of the rest of the EU.

The European Commission wants the Netherlands to keep the results secret because of fears they could influence other EU voters. Britain, where anti-EU party UKip is forecast to do very well, also voted on Thursday.

The Netherlands is electing 26 Dutch members of the European parliament.

According to the first exit poll, which is based on anonymous repeat voting at 44 representative polling stations, the Dutch result will be as follows:

CDA (Christian Democrat): 5 (was 5)

PVV (anti-immigration): 3 (was 4, then 5 when NL was given an extra seat)

VVD (right-wing Liberal): 3 (was 3)

PvdA (Labour): 2 (was 3)

D66 (Liberal democrat): 4 (was 3)

GroenLinks (left-wing green): 2 (was 3)

SGP/CU (orthodox Christian): 2 (was 2)

SP (socialist): 3 (was 1)

PvdA (animal rights): 1

50+: 1

Election evening in the Netherlands is traditionally dominated by televised debates and comment from politicians and experts as the results come in. However, without proper results, many party leaders said they will not comment.

In total, 19 parties took part in the elections.

Shock blog GeenStijl and opinion pollster Maurice de Hond are also attempting to collect enough individual polling station results to come up with a good estimate of how the Netherlands voted.

They have called on supporters to be at the polling stations when the votes are counted and pass on the results. GeenStijl said on Thursday evening it had registered vote counters at around 25% of the country’s 10,000 polling stations.

Polling stations in the Netherlands are public and the votes per party in each polling station are also announced to the people present at the time. Dutch election law does not stop people recording and distributing this information, he said.